/*
** $Id: lmathlib.c,v 1.119.1.1 2017/04/19 17:20:42 roberto Exp $
** Standard mathematical library
** See Copyright Notice in lua.h
*/

#define lmathlib_c
#define LUA_LIB

#include "lprefix.h"


#include <stdlib.h>
#include <math.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#undef PI
#define PI  (l_mathop(3.141592653589793238462643383279502884))


#if !defined(l_rand)    /* { */
#if defined(LUA_USE_POSIX)
#define l_rand()	random()
#define l_srand(x)	srandom(x)
#define L_RANDMAX	2147483647	/* (2^31 - 1), following POSIX */
#else
#define l_rand()  rand()
#define l_srand(x)  srand(x)
#define L_RANDMAX  RAND_MAX
#endif
#endif        /* } */


static int math_abs(lua_State *L) {
    if (lua_isinteger(L, 1)) {
        lua_Integer n = lua_tointeger(L, 1);
        if (n < 0) n = (lua_Integer) (0u - (lua_Unsigned) n);
        lua_pushinteger(L, n);
    } else
        lua_pushnumber(L, l_mathop(fabs)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_sin(lua_State *L) {
    lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_cos(lua_State *L) {
    lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_tan(lua_State *L) {
    lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_asin(lua_State *L) {
    lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_acos(lua_State *L) {
    lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_atan(lua_State *L) {
    lua_Number y = luaL_checknumber(L, 1);
    lua_Number x = luaL_optnumber(L, 2, 1);
    lua_pushnumber(L, l_mathop(atan2)(y, x));
    return 1;
}


static int math_toint(lua_State *L) {
    int valid;
    lua_Integer n = lua_tointegerx(L, 1, &valid);
    if (valid)
        lua_pushinteger(L, n);
    else {
        luaL_checkany(L, 1);
        lua_pushnil(L);  /* value is not convertible to integer */
    }
    return 1;
}


static void pushnumint(lua_State *L, lua_Number d) {
    lua_Integer n;
    if (lua_numbertointeger(d, &n))  /* does 'd' fit in an integer? */
        lua_pushinteger(L, n);  /* result is integer */
    else
        lua_pushnumber(L, d);  /* result is float */
}


static int math_floor(lua_State *L) {
    if (lua_isinteger(L, 1))
        lua_settop(L, 1);  /* integer is its own floor */
    else {
        lua_Number d = l_mathop(floor)(luaL_checknumber(L, 1));
        pushnumint(L, d);
    }
    return 1;
}


static int math_ceil(lua_State *L) {
    if (lua_isinteger(L, 1))
        lua_settop(L, 1);  /* integer is its own ceil */
    else {
        lua_Number d = l_mathop(ceil)(luaL_checknumber(L, 1));
        pushnumint(L, d);
    }
    return 1;
}


static int math_fmod(lua_State *L) {
    if (lua_isinteger(L, 1) && lua_isinteger(L, 2)) {
        lua_Integer d = lua_tointeger(L, 2);
        if ((lua_Unsigned) d + 1u <= 1u) {  /* special cases: -1 or 0 */
            luaL_argcheck(L, d != 0, 2, "zero");
            lua_pushinteger(L, 0);  /* avoid overflow with 0x80000... / -1 */
        } else
            lua_pushinteger(L, lua_tointeger(L, 1) % d);
    } else
        lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1),
                                         luaL_checknumber(L, 2)));
    return 1;
}


/*
** next function does not use 'modf', avoiding problems with 'double*'
** (which is not compatible with 'float*') when lua_Number is not
** 'double'.
*/
static int math_modf(lua_State *L) {
    if (lua_isinteger(L, 1)) {
        lua_settop(L, 1);  /* number is its own integer part */
        lua_pushnumber(L, 0);  /* no fractional part */
    } else {
        lua_Number n = luaL_checknumber(L, 1);
        /* integer part (rounds toward zero) */
        lua_Number ip = (n < 0) ? l_mathop(ceil)(n) : l_mathop(floor)(n);
        pushnumint(L, ip);
        /* fractional part (test needed for inf/-inf) */
        lua_pushnumber(L, (n == ip) ? l_mathop(0.0) : (n - ip));
    }
    return 2;
}


static int math_sqrt(lua_State *L) {
    lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
    return 1;
}


static int math_ult(lua_State *L) {
    lua_Integer a = luaL_checkinteger(L, 1);
    lua_Integer b = luaL_checkinteger(L, 2);
    lua_pushboolean(L, (lua_Unsigned) a < (lua_Unsigned) b);
    return 1;
}

static int math_log(lua_State *L) {
    lua_Number x = luaL_checknumber(L, 1);
    lua_Number res;
    if (lua_isnoneornil(L, 2))
        res = l_mathop(log)(x);
    else {
        lua_Number base = luaL_checknumber(L, 2);
#if !defined(LUA_USE_C89)
        if (base == l_mathop(2.0))
          res = l_mathop(log2)(x); else
#endif
        if (base == l_mathop(10.0))
            res = l_mathop(log10)(x);
        else
            res = l_mathop(log)(x) / l_mathop(log)(base);
    }
    lua_pushnumber(L, res);
    return 1;
}

static int math_exp(lua_State *L) {
    lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1)));
    return 1;
}

static int math_deg(lua_State *L) {
    lua_pushnumber(L, luaL_checknumber(L, 1) * (l_mathop(180.0) / PI));
    return 1;
}

static int math_rad(lua_State *L) {
    lua_pushnumber(L, luaL_checknumber(L, 1) * (PI / l_mathop(180.0)));
    return 1;
}


static int math_min(lua_State *L) {
    int n = lua_gettop(L);  /* number of arguments */
    int imin = 1;  /* index of current minimum value */
    int i;
    luaL_argcheck(L, n >= 1, 1, "value expected");
    for (i = 2; i <= n; i++) {
        if (lua_compare(L, i, imin, LUA_OPLT))
            imin = i;
    }
    lua_pushvalue(L, imin);
    return 1;
}


static int math_max(lua_State *L) {
    int n = lua_gettop(L);  /* number of arguments */
    int imax = 1;  /* index of current maximum value */
    int i;
    luaL_argcheck(L, n >= 1, 1, "value expected");
    for (i = 2; i <= n; i++) {
        if (lua_compare(L, imax, i, LUA_OPLT))
            imax = i;
    }
    lua_pushvalue(L, imax);
    return 1;
}

/*
** This function uses 'double' (instead of 'lua_Number') to ensure that
** all bits from 'l_rand' can be represented, and that 'RANDMAX + 1.0'
** will keep full precision (ensuring that 'r' is always less than 1.0.)
*/
static int math_random(lua_State *L) {
    lua_Integer low, up;
    double r = (double) l_rand() * (1.0 / ((double) L_RANDMAX + 1.0));
    switch (lua_gettop(L)) {  /* check number of arguments */
        case 0: {  /* no arguments */
            lua_pushnumber(L, (lua_Number) r);  /* Number between 0 and 1 */
            return 1;
        }
        case 1: {  /* only upper limit */
            low = 1;
            up = luaL_checkinteger(L, 1);
            break;
        }
        case 2: {  /* lower and upper limits */
            low = luaL_checkinteger(L, 1);
            up = luaL_checkinteger(L, 2);
            break;
        }
        default:
            return luaL_error(L, "wrong number of arguments");
    }
    /* random integer in the interval [low, up] */
    luaL_argcheck(L, low <= up, 1, "interval is empty");
    luaL_argcheck(L, low >= 0 || up <= LUA_MAXINTEGER + low, 1,
                  "interval too large");
    r *= (double) (up - low) + 1.0;
    lua_pushinteger(L, (lua_Integer) r + low);
    return 1;
}


static int math_randomseed(lua_State *L) {
    l_srand((unsigned int) (lua_Integer) luaL_checknumber(L, 1));
    (void) l_rand(); /* discard first value to avoid undesirable correlations */
    return 0;
}


static int math_type(lua_State *L) {
    if (lua_type(L, 1) == LUA_TNUMBER) {
        if (lua_isinteger(L, 1))
            lua_pushliteral(L, "integer");
        else
            lua_pushliteral(L, "float");
    } else {
        luaL_checkany(L, 1);
        lua_pushnil(L);
    }
    return 1;
}


/*
** {==================================================================
** Deprecated functions (for compatibility only)
** ===================================================================
*/
#if defined(LUA_COMPAT_MATHLIB)

static int math_cosh (lua_State *L) {
  lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1)));
  return 1;
}

static int math_sinh (lua_State *L) {
  lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1)));
  return 1;
}

static int math_tanh (lua_State *L) {
  lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1)));
  return 1;
}

static int math_pow (lua_State *L) {
  lua_Number x = luaL_checknumber(L, 1);
  lua_Number y = luaL_checknumber(L, 2);
  lua_pushnumber(L, l_mathop(pow)(x, y));
  return 1;
}

static int math_frexp (lua_State *L) {
  int e;
  lua_pushnumber(L, l_mathop(frexp)(luaL_checknumber(L, 1), &e));
  lua_pushinteger(L, e);
  return 2;
}

static int math_ldexp (lua_State *L) {
  lua_Number x = luaL_checknumber(L, 1);
  int ep = (int)luaL_checkinteger(L, 2);
  lua_pushnumber(L, l_mathop(ldexp)(x, ep));
  return 1;
}

static int math_log10 (lua_State *L) {
  lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1)));
  return 1;
}

#endif
/* }================================================================== */



static const luaL_Reg mathlib[] = {
        {"abs", math_abs},
        {"acos", math_acos},
        {"asin", math_asin},
        {"atan", math_atan},
        {"ceil", math_ceil},
        {"cos", math_cos},
        {"deg", math_deg},
        {"exp", math_exp},
        {"tointeger", math_toint},
        {"floor", math_floor},
        {"fmod", math_fmod},
        {"ult", math_ult},
        {"log", math_log},
        {"max", math_max},
        {"min", math_min},
        {"modf", math_modf},
        {"rad", math_rad},
        {"random", math_random},
        {"randomseed", math_randomseed},
        {"sin", math_sin},
        {"sqrt", math_sqrt},
        {"tan", math_tan},
        {"type", math_type},
#if defined(LUA_COMPAT_MATHLIB)
        {"atan2", math_atan},
        {"cosh",   math_cosh},
        {"sinh",   math_sinh},
        {"tanh",   math_tanh},
        {"pow",   math_pow},
        {"frexp", math_frexp},
        {"ldexp", math_ldexp},
        {"log10", math_log10},
#endif
        /* placeholders */
        {"pi", NULL},
        {"huge", NULL},
        {"maxinteger", NULL},
        {"mininteger", NULL},
        {NULL, NULL}
};


/*
** Open math library
*/
LUAMOD_API int luaopen_math(lua_State *L) {
    luaL_newlib(L, mathlib);
    lua_pushnumber(L, PI);
    lua_setfield(L, -2, "pi");
    lua_pushnumber(L, (lua_Number) HUGE_VAL);
    lua_setfield(L, -2, "huge");
    lua_pushinteger(L, LUA_MAXINTEGER);
    lua_setfield(L, -2, "maxinteger");
    lua_pushinteger(L, LUA_MININTEGER);
    lua_setfield(L, -2, "mininteger");
    return 1;
}

